Which of the following best defines "arson"?

The definition of arson specifically involves the intentional act of setting fire to property. This action is not only defined by the act of igniting a fire but also by the intent behind it, which is typically to cause damage or destruction to that property. Arson is considered a serious crime because it poses significant risks to life and safety, not only to the property owner but also to firefighters and the general public.

The other choices describe different criminal activities: unlawful entry with intent is known as burglary, taking property by force describes theft or robbery, and threatening someone for property relates to extortion. Each of these actions has distinct legal definitions and implications, distinguishing them from the act of arson.